Users appreciate WP-Optimize for its comprehensive feature set, including database cleaning, caching, and minifying JavaScript, which help improve website speed and performance. It effectively removes old revisions and optimizes databases, which is particularly useful for maintaining a streamlined backend. Its image compression, while beneficial, has faced issues, with several users noting that it no longer works and complaints about developers not addressing the problem. Some users experienced plugin conflicts, causing minor issues like calendar glitches or blocking functionalities like counters and sliders. Despite these drawbacks, the plugin is highly recommended for its ease of use, effectiveness, and positive impact on site performance and speed.